The DPRK’s central news agency is reporting
that its nuclear experiments have been resumed and that it’s successfully conducted an implosion test on weapons-grade plutonium:

On 9 October, North Korea announced through the KCNA, that it had conducted a nuclear experiment. It appears that the goal was to push through the test on the day before North Korea’s Korean Workers Party’s Founding Day [whatever that is in English–SRK] and make a display of the power of the Kim Jong-il regime. “Our scientific research division has conducted underground nuclear experimentation safely and successfully,” the report states. It also says, “In these experiments, which were conducted using scientific and meticulous calculations, it was confirmed that there was no danger at all from radiation leakage.”

Pyongyang apparently sent word to Beijing less than a half-hour before the test was conducted. There’s no substantive reaction
from the government here yet.

The timing, especially, throws a wrench into the works because Prime Minister Abe met with
PRC President Hu Jintao over the weekend:

During the meeting, Abe urged the Chinese leaders to cooperate with Japan to stop Pyongyang from carrying out the nuclear test. The Chinese side responded that Beijing would pressure Pyongyang to refrain from the test.

As to Pyongyang’s nuclear test plan, Abe told Hu, “It is a serious threat to peace and security in the international community and Japan will never tolerate it.”

This was Abe’s first visit abroad as head of state; that he went to China and not the US is significant. That Japan-PRC relations may thaw, because Hu is willing to give Abe the benefit of the doubt about the Yasukuni Shrine, doubtless worries the DPRK because it needs to maintain its position by playing other parties off each other. It will be interesting to see Beijing’s reaction to the announcement, which I haven’t heard reported yet.